2 adverbs to describe how to rarefies

Then, the music growing fainter and fainter as the atmosphere became more celestially rarefied, I felt the supporting Hand going away from me.

Hail is the congelation of drops of rain in irregular forms, always sudden,by some attributed to electricity and currents of air violently rarefied by it, and by others to rain-drops falling through a cold stratum of air and suddenly congealed.

2 adverbs to describe how to  rarefies  - Adverbs for  rarefies